Wells are drilled into the earth's crust using a drilling rig. Pipe strings are lengthened by threadably coupling add-on pipe segments to the proximal end of the pipe string. The pipe string is generally suspended within the borehole using a rig floor-mounted spider as each new pipe segment or stand is coupled to the proximal end of the pipe string just above the spider. A single joint elevator is used to grip and secure the segment or stand to a hoist to lift the segment or stand into position for threadably coupling to the pipe string.
For installing a string of casing, existing single joint elevators generally comprise a pair of hinged body halves that open to receive a joint of pipe and close to secure the pipe within the elevator. Elevators are specifically adapted tor securing and lifting pipe having conventional connections. A conventional connection comprises an internally threaded sleeve that receives and secures one externally threaded end from each of two pipe segments to secure the segments in a generally abutting relationship. The internally threaded sleeve is first threaded onto the end of a first segment of pipe to form a “box end.” The externally threaded “pin end” of the second segment of pipe is threaded into the box end to complete the connection between the segments. Typical single joint elevators have a circumferential shoulder that is forms a circle upon closure of the hinged body halves. The shoulder of the elevator engages the shoulder formed between the end of the sleeve and the pipe segment. Conventional single joint elevators cannot grip a pipe segment having integral connections (having no circumferential shoulder), and conventional single joint elevators can only grip a pipe segment at the threaded sleeve that secures the connection.
Conventional elevators are difficult to use on pipe segments that are not conveniently accessible. For example, casing segments are often moved to the rig floor from a horizontal pipe rack and presented to the rig floor at a “V”-door. A conventional elevator requires enough clearance to close the hinged body halves around the casing segment. Depending on the length of the pipe and the proximity of the floor or other rig structures, there may be insufficient clearance around the casing segment for installing a conventional single joint elevator, often requiring repositioning of the casing segment so that the single joint elevator can be installed around the casing segment. Even if repositioning of each casing segment takes only a few seconds, delays for repeatedly repositioning casing segments in the V-door consumes a substantial amount of rig time.
What is needed is a single joint elevator that is securable to a pipe at multiple positions along the length of the pipe segment, and not only at the end connection. What is needed is a single joint elevator that is adapted for securing to the pipe segment notwithstanding close proximity of the rig floor or other rig structure. What is needed is a single joint elevator that can be used to lift single pipe segments without repositioning the pipe segment to secure the single joint elevator. What is needed is a versatile single joint elevator that facilitates lifting both a pipe segment having integral connections and a pipe segment having a conventional connection with a threaded sleeve received onto the end of the pipe segment.